fix(lambda): LoggingConfig default error (#28973)

### Issue # (if applicable)

Fixes bug in LoggingFormat `@default`

### Reason for this change
Incorrect
#28114 related issue


### Description of changes
Not much to describe here. 

### Description of how you validated changes

Shouldn't need any as there is integ tests from this pr
#28942

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)



BREAKING CHANGE: changing the default type of `lambda.loggingFormat`. Previously it was a string `"Text format"`, not it is an enum `LoggingFormat.TEXT`.



*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: ConnorRobertson

packages/aws-cdk-lib/aws-lambda/lib/function.ts

@@ -521,7 +521,7 @@ export interface FunctionOptions extends EventInvokeConfigOptions {
 
   /**
    * Sets the loggingFormat for the function.
-   * @default Text format
+   * @default LoggingFormat.TEXT
    */
   readonly loggingFormat?: LoggingFormat;